Speaking of simple ram air systems: I have this extra 8" vent from my recent bathroom vent install and I've thought about cutting the necessary hole into my hood to add it. All I would need to do is mount the airbox upside down (so it sucks from the hood vs. the fender well and bolt this to the hood.
It's either that or make it into a roof scoop.
I'm sure it will be good for another 20HP (as a hood scoop vs. an roof vent/scoop) -g
PS. If you want your own, check out Home Depot Racing Supply.